In fact, the crayfish have died due to high water temperatures, SLU writes on its website.
”Warm water does indeed make the signal crayfish grow faster and become larger, but high water temperature also leads to the signal crayfish dying when the water is not oxygenated sufficiently”, explains Patrik Bohman, environmental analyst.
Another reason why you can find dead signal crayfish on the beach, for example at Vänern, is that the crayfish are extra sensitive when they molt. After a storm, it can die from powerful waves.
When the signal crayfish is stressed, it can also die from plague, which has occurred in Hjälmaren, according to SLU.
